Sudden pressure relay testing device



Oct. 15, 1963 P. w. RUSSELL SUDDEN PRESSURE RELAY TESTING DEVICE 2sheets-sheet 1 Filed July 50, 1959 FIG. I

INVENTOR. PHILLIP W. RUSSELL BY wmQ-bmimu g g g Oct. 15, 1963 P. w.RUSSELL SUDDEN PRESSURE RELAY TESTING DEVICE 2 Sheets-Sheet 2 Filed July50, 1959 INVENTOR. PHILLIP w. RUSSELi L A TORNEYS mus-C.

mhE n E J- won United States Patent 3,106,833 SUDDEN PRESSURE RELAYTESTING DEVICE Phillip W. Russell, 14015 Superior Ave., Cleveland, OhioFiled July 30, 1959, Ser. No. 830,698 Ciairns. (Cl. 73-4) This inventionrel-ates to means for testing the internal components of electricaltransformer sudden pressure relays, and more particularly relates to thetesting of the tripping and resetting functions of the relay as well asthe response times of these functions.

A sudden pressure relay is a protective device usually mounted on a sideof a gas-cushioned, liquid immersed, electrical transformer in theregion of the gas space, the transformer referred to being of the heavyduty industrial type used by utility companies and the like for handlinghigh voltage electricity. A sudden pressure relay is designed foralarm-trip circuit closing on occurrence of a fault in the transformerwhich produces an abnormal rise of pressure. Inasmuch as this apparatusis factory sealed and not susceptible to direct manual inspection perse, it is normal procedure to remove the relay from the transformer andtransport it to a laboratory where it can be tested by apparatusdesigned to simulate the functioning of a transformer. Once the suddenpressure relay is removed from the transformer, the transformer gas islost to the atmosphere, resulting in downtime for the transformer untilthe relay can be returned, installed, and the transformer recharged withgas. With my invention, it is not necessary to remove the suddenpressure relay from the transformer, inasmuch as the invention isadapted to make all necessary checks right in the field of the internalcomponents of the relay including the bellows means, the limit switchmeans, sub-relay means, and contacts associated with the sub-relaymeans.

The present customary method of checking sudden pressure relays includesthe application of pressure under laboratory controlled conditions onthe transformer side of the relay to determine the proper functioning ofthe internal mechanisms of the relay. It is my concept, however, toreverse thismethod and reduce pressure on the sudden pressure relay sideof the transformer to achiev the same net influence upon the suddenpressure relay mechanisms. The degree of pressure decrease in the suddenpressure relay may be calibrated to achieve.

the same effect as a corresponding pressure increase on the transformerside. Inasmuch as a sudden pressure relay depends upon differentialpressure for operation, it is, therefore, immaterial whether theincrease of pressure be on the transformer side or a correspondingdecrease or" pressure be on the sudden pressure relay side.

It is, therefore, the general object of my invention to provide a fieldtesting unit for inspecting and checking the functioning of suddenpressure relays without the necessity of removing the relay from thetransformer resulting in all of the enumerated disadvantages of thisprocedure.

The features of this invention which are believed to be novel are setforth with particularity in the appended claims. The invention itself,however, both as to its organization and use, together with furtherobjects and advantages thereof, may best be understood by reference tothe following description taken in conjunction with the accompanyingdrawings in which:

FIGURE 1 is a perspective elevational view partly in section of atypical sudden pressure relay in association with a schematicrepresentation of the subject invention; and

FIGURE 2 is a schematic wiring diagram of a preferred embodiment of myinvention shown in association with the schematic wiring diagram of asudden pressure relay.

Referring now to FIGURE 1 in greater detail, a typical sudden pressurerelay 10 is shown to include a bellows 12, adapted to actuate a limitswitch 14 connected to a seal-in sub-relay means 15. The sudden pressurerelay is hermetically sealed to a mounting base 18 and isolated from thetransformer mounting base 20 except for a small pressure equalizer plug22. This equalizer plug 22 is provided with a small bore 24, permittingnormal transformer operation over its entire pressure range withoutgiving a false alarm. The pressure equalizer plug 22 will act tothrottle any rate of pressure change of greater magnitude than thatexperienced in normal operation so as to effect a pressure differentialbetween the relay case and the transformer case, and thus operate thebellows 12 and the pressure actuated limit switch 14.

The general organization of my invention includes solenoid operatedvalve means 39, connected directly to the sudden pressure relay 10 bysuitable tube means 32 and connected to a plug 34 which is provided asstandard equipment in the relay 10. I also connect to the electricaljack 50, which is also standard equipment with the sudden pressure relay10, circuitry in association with timer means 36 and switch means 8-3adapted to energize the timer means 36 at the same time that thesolenoid operated valve means is actuated. The solenoid operated valvemeans 30 comprises, in a preferred embodiment of my invention, aplurality of valves 30a, 30b, 36c, and 3011', each of which is providedwith a port to exhaust .gas from the sudden pressure relay it to theatmosphere at a predetermined rate in pounds per second. Thus, byopening the solenoid valve 30a, for instance, the timer 36 is startedand will continue to run until the pressure in the sudden pressure relay10 drops to a predetermined level. At this time, the bellows 12 in thesudden pressure relay 10 will operate or expand to act-uate the limitswitch 14 and to stop the timer 36 by circuitry generally designated at40 which I incorporate with the seal-in sub-relay 15 of the suddenpressure relay 10. The provision of extra solenoid operated valves 30band 30c, having ports of different sizes enables the testing of suddenpressure relays having different timing constants. I also provide pilotlight circuitry including pilot lights PL-l, PL-Z, PL-3, PL4, and PL-Sto monitor the operation of relay contacts C-l, C-2, C-3, 04, C-S, andC-6 while at the same time testing the general functioning of thesub-relay 16.

To check the reset time of the bellows 12, I provide circuitry whichconnects the sudden pressure relay 10 to a solenoid operated valve 30dproviding substantially instantaneous exhaust capacity. Additionally,this circuitry alsoprovides for a 15 second delay period for the purposeof assuring that all pressure has been released from the sudden pressurerelay 10. Thereafter, the timer 36 is automatically started and willcontinue to run until the bellows 12 recovers its normal collapsedcondition, thereby permitting the limit switch 14 to re-set. When thelimit switch 14 re-sets, the timer then stops.

Referring now to FIGURE 2 in greater detail, the test unit circuitry ofFIGURE 2 can be best described and understood by tracing through atypical test operation. Once my testing unit is connected to the suddenpressure relay 10, the following initial conditions will exist. Anadaptor 44 is secured to the sudden pressure relay test plug 34connecting the interior of the sudden pressure relay 10 to a manifold 48of solenoid operated valves 30a, 30b, 30c, and 30d. Sudden pressurerelay receptacle 50 is engaged by test unit plug 52 to form a couplinggenerally designated at 53 and connecting the seal-in sub-relay 15 ofthe sudden pressure relay with the circuitry 40 of the test unit. Switch8- is closed, switch S-Z is open, and switch 8-3 is at the open orterminal T-t) position. A source of power is applied across lines L1 andL2 and a pilot light PL-1 is connected across these lines to indicatethat the power is on. In FIGURE 2 a separate source of power acrosslines L3 and L4 is shown inasmuch as sudden pressure relays may havedifferent power requirements from the test unit itself. Thisarrangement, however, is optional. Associated with the separate powersource lines L3 and L4 is a pilot light PL-Z provided to indicate whenthese lines are energized. Assuming the above stated initial condition,the circuitry may be traced from L1 through coupling 53 connection J,normally closed relay C-S, receptacle connection K, and pilot light PL-3to line L2. The energization of pilot light PL-3 will indicate thatcoupling connections I and K and normally closed contact -8 arefunctioning properly.

The bellows of each sudden pressure relay will have a manufacturersspecification time constant for expanding under the influence of apredetermined pressure. In order to check this time constant, thefollowing procedure is followed with my test unit. Switch -3 is placedat terminal position T1 and switch 8-2 is closed permitting power fromL1 to pass through switch S2, terminal T-1 to magnetic valve 30a.Magnetic valve 30a is then energized to open an exhaust port which willdecrease the pressure from sudden pressure relay at a rate simulating apressure buildup in the transformer. At the same time, the energy fromline L1 will pass through coupling connection G, normally closed contactC-4, coupling connection H, switch S2, terminal T-1, and normally closedcontact (2-3 to the Y terminal of the timer 36, thereby activating thetimer. If the timer runs, it is then determined that coupling points G,H, and normally closed contacts 03 and 0-4 are [functioning properly forthis portion of the test.

When the pressure in the sudden pressure relay 10 is reduced to apredetermined level sufficient to cause the bellows to expand, limitswitch 14 is closed permitting energy from L4 to pass through couplingconnection A, limit switch 14, and sub-relay 16. When sub-relay 16 isenergized, contacts C-S, 0-6, C-7, and C9 will close and contacts 0-4and 08 will open. When contact C-4 opens, the timer circuitry will beinterrupted and the timer will stop. This tests the contact 04 opencondition and, at the same time, pilot light PL-3 will go out therebyverifying the open condition of contact 0-8. Pilot light PL4 will beenergized through contact 0-7 and coupling connection E, thereby testingthese two units. At the same time, pilot light PL-5 will be energizedthrough coupling connection D, contact C-6 and coupling connection L totest these units. This completes the test for the switch S3 in theterminal T-1 position. In order to repeat the test, or in order to testthe relay for a different time differential, switch 8-3 is moved to theterminal T-O position and switch 8-1. is opened. Magnetic valve 30a willthen close and the pressure in the sudden pressure relay 10 will thenbuild up by virtue of bleeding through the bore 24 in equalizer plug 22connecting the sudden pressure relay to the transformer. After thepressure differential has decreased sufiiciently, the bellows 12 willcommence to collapse again into its normal position and limit switch 14will open to deenergize sub-relay 16. When sub-relay 16 is de-energized,pilot light PL-4 and pilot light PL-S will go out and pilot light PL-3will re-light. Switch 8-2 is then reopened and sufiicient time is thenallowed for the pressure equalization between the sudden pressure relayand the transformer before making the next test. In order to test thesudden pressure relay for other time constants, such as determined bymagnetic valves 30b and 300, the above procedure is repeated by placingswitch S 3 in terminal positions T-2 and T-3, respectively.

The other test of significance is that of timing the bellows 12 todetermine if it collapses within the prescribed time set by themanufacturer after pressure has become equalized between the suddenpressure relay 10 and the transformer. To begin the test, the test unitis put in the initial test status as described hereinabove, Switch 5-3is then placed in the terminal T-4 position, switch S-1 is opened andswitch 8-2 is closed. Subrelays and 62 are then energized across linesL1 and L2 through normally closed contact C4. Sub-relay 62 will operateto open contact C-3, thereby removing power from the timer 36, andcontact C-2 will close to energize magnetic solenoid valve 30d. Magneticvalve 30d is then opened to substantially intantaneously exhaust thepressure from sudden pressure relay 10. Sub-relay 16 will again beenergized by the closing of limit switch .14, and sub-relay 60, which isa 15 second delay relay, will open contact C-1 at the end of the delayperiod. This will de-energize sub-relay 62, thereby caus ing contact 0-2to open and de-energize magnetic valve solenoid 30d. Concurrently, poweris applied to the timer 36 through contact C-'3, enabling the timer torun until the pressure in the sudden pressure relay 10 is sufficientlyhigh to collapse bellows 12 and open limit switch 14. When limit switch14 opens, sub-relay 16 will be de-energized and contact 0-9 will openremoving power from the timer. This then completes the re-set test. Byobserving the time logged by the timer, in both the bellows expandingtest and the bellows re-set test, it is possible to determine whetherthe bellows are functioning in accordance with manufacturersspecifications. At the same time, all of the internal elements of thesudden pressure relay are monitored and checked for opening and closingconditions.

In summation, my invention provides the advantages of a device which iscompact and portable, thereby making it available for use in the field;it is efficient and ecoonmical to operate, and requires less man powerfor operation; it eliminates the necessity for removing the suddenpressure relay from the transformer, thereby insuring practically noloss of gas pressure in the transformer; and it eliminates transformerdowntime and labor costs involved in removing, testing and replacingsudden pressure relays. My invention is also simple in principle,thereby making it possible for personnel with a minimum of instructionand training to satisfactorily use the equipment.

While only one embodiment of my invention has been disclosed anddiscussed hereinabove, still other arrangements and modifications willappear to those skilled in the art upon a reading of the specificationtaken in conjunction with the drawings, and other arrangements may beresorted to without departing from the spirit and scope of the inventionas defined by the appended claims.

I claim:

1. A testing device for a gas filled, positive pressure operatedtransformer sudden pressure relay of the class described having pressuresensitive means, said testing device comprising: a plurality of presetsolenoid valve means selectively communicable with the interior of saidsudden pressure relay to exhaust pressure from the interior thereof at apredetermined rate; timing means; and means to open one of said valvemeans and to start said timer; and means responsive to the actuation ofsaid pressure sensitive means to stop said timer.

2. A testing device for a gas filled, positive pressure operatedtransformer sudden pressure relay of the class described having pressuresensitive relay means, said testing device comprising: means to exhaustpressure from the interior of said sudden pressure relay at apredetermined rate including preset solenoid valve means communicablewith the interior of said sudden pressure relay; timing means; means tosimultaneously open said valve means and start said timer; and meansresponsive to the actuation of said pressure sensitive relay means tostop said timer.

3. A testing device for a gas filled, positive pressure operatedtransformer sudden pressure relay of the class described, havingpressure responsive means, said testing device comprising: means toexhaust pressure at a predetermined rate from the interior of a saidsudden pressure relay; timing means; first test means including means tosimultaneously open said exhaust means and to start said timing means;and means to stop said timing means responsive to a first actuation ofsaid pressure responsive means; second test means including means tosimultaneously open said exhaust means and to deactivate said timingmeans; means responsive to a first actuation of said pressure responsivemeans to simultaneously close said exhaust means and to activate saidtiming means; and means responsive to a second actuation of saidpressure responsive means to deactivate said timer.

4. A testing device for a gas filled, positive pressure operatedtransformer sudden pressure relay of the class described having pressureresponsive means, said testing device comprising: first preset valvemeans adapted to exhaust pressure from said sudden pressure relay at acontrolled rate; second preset valve means adapted to substantiallyinstantaneously exhaust pressure from said sudden pressure relay; timingmeans; first test means circuitry including means to simultaneously opensaid first valve means and to start said timing means; and means to stopsaid timing means responsive to a first movement of said pressureresponsive means; second test means circuitry including means tosimultaneously open said second valve means and to deactivate saidtiming means; means responsive to a first movement of said pressureresponsive means to simultaneously close said second valve means and toactivate said timing means; means responsive to a second movement ofsaid pressure responsive means to deactivate said timer; and means toselect and connect either said first test means circuitry or said secondtest means circuitry to said first or second valve means, respectively.

5. A testing device for a gas filled, positive pressure operatedtransformer sudden pressure relay of the class described having pressureresponsive bellows means adapted to close and open limit switch meansresponsive to bellows means expansion and contraction movementsrespectively, said testing device comprising: an exhaust manifoldincluding normally closed first and second solenoid valves, said firstsolenoid valve being preset to exhaust pressure from said suddenpressure relay at a predetermined controlled rate, said second solenoidvalve being preset to exhaust pressure from said sudden pres sure relaysubstantially instantaneously, means to connect said manifold to theinterior of said sudden pressure relay; timing means; power means; firstcircuitry means including selector switch means connecting said powermeans to said first circuit means to simultaneously energize and opensaid first solenoid valve and energize and start said timing means; andmeans to de-energize said timing means responsive to expansion of saidbellows means; second circuitry means; said selector switch. means beingadapted to disconnect said first circuitry means and to connect saidsecond circuitry means to said power means to simultaneously open saidsecond solenoid valve and to deactivate said timing means; meansresponsive to expansion of said bellows means to simultaneously closesaid exhaust means and to activate said timing means; and meansresponsive to contraction of said bellows means to deactivate saidtiming means.

6. A testing device for a gas filled, positive pressure operatedtransformer sudden pressure relay of the class described having pressureresponsive bellows adapted to close and open limit switch meansresponsive to bellows expansion and contraction movement respectively,said testing device comprising: an exhaust manifold including preset,normally closed first and second solenoid valves having differentexhaust rate capacities; means to connect said manifold to the interiorof said sudden pressure relay; power means; timing means; firstcircuitry means including selector switch means to connect said powermeans to said first circuitry means to simultaneously energize and opensaid first solenoid valve and energize and start said timing means; andmeans to deenergize said timing means responsive to expansion of saidbellows; second circuitry means including first and second sub-relays;said selector switch means being adapted to disconnect said firstcircuitry means and to connect said second circuitry means to said powermeans to simultaneously energize said first and second subrelays, saidsecond sub-relay being delay acting; first and second pairs of contacts,said first sub-relay opening said first pair of contacts to deactivatesaid timer, said second sub-relay closing said second pair of contactsto energize and open said second solenoid valve; a third pair ofnormally closed contacts in series between said first and secondsub-relays adapted to be opened by said delay acting second sub-relay todeenergize said first sub-relay, close said first contacts to start saidtiming means, and open said second contacts to close said secondsolenoid valve; and means to deactivate said timer responsive tocontraction of said bellows.

7., In a gas filled, positive pressure operated transformer suddenpressure relay of the class described, and having relay means adapted tobe actuated by expansion and contraction of a bellows responsive tochanges of pressure within said relay, apparatus for testing theperformance of said bellows and relay means comprising: a presetsolenoid operated valve connected to the interior of said suddenpressure relay; timing means; circuitry including means tosimultaneously actuate said valve to the open position and to start saidtimer; and means to stop said timer responsive to actuation of saidrelay means by expansion of said bellows.

8. In a gas filled, positive pressure operated transformer suddenpressure relay of the class described and having relay means adapted tobe actuated by expansion and contraction of a bellows responsive tochanges of pressure within said relay, apparatus for testing theperformance of said bellows and relay means comprising: a first presetsolenoid operated valve connected to the interior of said suddenpressure relay; timing means; circuitry including means tosimultaneously actuate said valve to the open position and to start saidtimer; and means to stop said timer responsive to actuation of saidrelay means by expansion of said bellows; a second solenoid operatedpreset valve connected to the interior of said sudden pressure relay;circuitry including means to simultaneously actuate said second valve tothe open position and to deactivate said timer; means including saidrelay means energized responsive to the expansion of said bellows toclose said valve and to start said timer; and said relay means beingdeenergized by the contraction of said bellows to stop said timer.

9. In a gas filled, positive pressure operated transformer suddenpressure relay of the class described having bellows responsive tochanges of pressure within said relay; relay means controlling theactuation of a plurality of relay contacts, and said relay means beingadapted to be closed and opened responsive to the expansion andcontraction of said bellows, the improvement in apparatus {for testingthe performance of said bellows and said relay means comprising: apreset solenoid operated valve connected to the interior of said suddenpressure relay; tinting means; circuitry including monitoring means inseries with said relay means and said relay contacts; means tosimultaneously actuate said valve to the open position and to start saidtimer; and means to stop said timer responsive to actuation of saidrelay means by expansion of said bellows.

10. In a gas filled, positive pressure operated transtformer suddenpressure relay of the class described having bellows responsive tochanges or pressure within said relay; relay means controlling theactuation of a plurality of relay contacts, and said relay means beingadapted to be closed and opened responsive to the expansion andcontraction of said bellows, the improvement in apparatus for testingthe performance of said bellows and said relay means comprising: apreset solenoid operated valve connected to the interior of said suddenpressure relay; timing means; circuitry including monitoring means inseries with said relay means and said relay contacts; means tosimultaneously actuate said valve to the open position and to start saidtimer; and means to stop said timer responsive to actuation of saidrelay means by expansion of said bellows; a second solenoid operatedpreset valve connected to the interior of said sudden pressure relay;circuitry including means to simultaneously actuate said second valve tothe open position and to References Cited in the file of this patentUNITED STATES PATENTS Coon et a1 July 7, 1959 OTHER REFERENCESElectronics, May 1951, pages 126129 Automatic Calibration of RadiosondeBaroswitches."

1. A TESTING DEVICE FOR A GAS FILLED, POSITIVE PRESSURE OPERATEDTRANSFORMER SUDDEN PRESSURE RELAY OF THE CLASS DESCRIBED HAVING PRESSURESENSITIVE MEANS, SAID TESTING DEVICE COMPRISING: A PLURALITY OF PRESETSOLENOID VALVE MEANS SELECTIVELY COMMUNICABLE WITH THE INTERIOR OF SAIDSUDDEN PRESSURE RELAY TO EXHAUST PRESSURE FROM THE INTERIOR THEREOF AT APREDETERMINED RATE; TIMING MEANS; AND MEANS TO OPEN ONE OF SAID VALVEMEANS AND TO START SAID TIMER; AND MEANS RESPONSIVE TO THE ACTUATION OFSAID PRESSURE SENSITIVE MEANS TO STOP SAID TIMER.